#include "int128.h"

/*
  Name: int128.cpp
  Copyright: Copyright (C) 2005, Jan Ringos
  Author: Jan Ringos, http://Tringi.Mx-3.cz
  
  Version: 1.1
*/

#include <memory>
#include <cmath>

// IMPLEMENTATION

const char * int128::toString (uint32_t radix) const throw () {
    if (!*this) return "0";
    if (radix < 2 || radix > 37) return "(invalid radix)";

    static char sz [256];
    memset (sz, 0, 256);

    int128 r;
    int128 ii = (*this < 0) ? -*this : *this;
    int i = 255;
    int128 aux =  radix;
    
    while (!!ii && i) {
        ii = ii.div (aux, r);
        sz [--i] = r.toInt () + ((r.toInt () > 9) ? 'A' - 10 : '0');
    };
    
    if (*this < 0)
        sz [--i] = '-';
    
    return &sz [i];
};

int128::int128 (const char * sz) throw ()
    : lo (0u), hi (0) {
    
    if (!sz) return;
    if (!sz [0]) return;
    
    uint32_t radix = 10;
    uint32_t i = 0;
    bool minus = false;

    if (sz [i] == '-') {
        ++i;
        minus = true;
    }
    
    if (sz [i] == '0') {
        radix = 8;
        ++i;
        if (sz [i] == 'x') {
            radix = 16;
            ++i;
        }
    }
    
    for (; i < strlen (sz); ++i) 
{
        uint32_t n = 0;
        if (sz [i] >= '0' && sz [i] <= (('0' + (int) radix) < '9'))
            n = sz [i] - '0';
        else if (sz [i] >= 'a' && sz [i] <= 'a' + (int) radix - 10)
            n = sz [i] - 'a' + 10;
        else if (sz [i] >= 'A' && sz [i] <= 'A' + (int) radix - 10)
            n = sz [i] - 'A' + 10;
        else
            break;
        
        (*this) *= radix;
        (*this) += n;
    }
    
    if (minus)
        *this = int128(0) - *this;

    return;
};

int128::int128 (const float a) throw ()
    : lo ((uint64_t) fmodf (a, 18446744073709551616.0f)),
      hi ((int64_t) (a / 18446744073709551616.0f)) {};

int128::int128 (const double & a) throw ()
    : lo ((uint64_t) fmod (a, 18446744073709551616.0)),
      hi ((int64_t) (a / 18446744073709551616.0)) {};

int128::int128 (const long double & a) throw ()
    : lo ((uint64_t) fmodl (a, 18446744073709551616.0l)),
      hi ((int64_t) (a / 18446744073709551616.0l)) {};

float int128::toFloat () const throw () {
    return (float) this->hi * 18446744073709551616.0f
         + (float) this->lo;
};

double int128::toDouble () const throw () {
    return (double) this->hi * 18446744073709551616.0
         + (double) this->lo;
};


int128 & int128::operator= (const float &a) throw ()
{
      lo = ((uint64_t) fmodf (a, 18446744073709551616.0f));
      hi = ((int64_t) (a / 18446744073709551616.0f)); 
	  return *this;
}

int128 & int128::operator= (const double & a) throw ()
{
     lo = ((uint64_t) fmod (a, 18446744073709551616.0));
      hi = ((int64_t) (a / 18446744073709551616.0));
	return *this;
}

int128 & int128::operator= (const long double & a) throw ()
{
     lo = ((uint64_t) fmodl (a, 18446744073709551616.0l));
      hi = ((int64_t) (a / 18446744073709551616.0l));
	return *this;
}


long double int128::toLongDouble () const throw () {
    return (long double) this->hi * 18446744073709551616.0l
         + (long double) this->lo;
};

int128 int128::operator - () const throw () {
    if (!this->hi && !this->lo)
        // number is 0, just return 0
        return *this;
    else
        // non 0 number
        return int128 (-this->lo, ~this->hi);
};

int128 int128::operator ~ () const throw () {
    return int128 (~this->lo, ~this->hi);
};

int128 & int128::operator ++ () {
    ++this->lo;
    if (!this->lo)
        ++this->hi;
    
    return *this;
};

int128 & int128::operator -- () {
    if (!this->lo)
        --this->hi;
    --this->lo;
    
    return *this;
};

int128 int128::operator ++ (int) {
    int128 b = *this;
    ++ *this;
    
    return b;
};

int128 int128::operator -- (int) {
    int128 b = *this;
    -- *this;
    
    return b;
};

int128 & int128::operator += (const int128 & b) throw () {
    uint64_t old_lo = this->lo;

    this->lo += b.lo;
    this->hi += b.hi + (this->lo < old_lo);
    
    return *this;
};

int128 & int128::operator *= (const int128 & b) throw () {
    if (!b)
        return *this = 0u;
    if (b == 1u)
        return *this;
        
    int128 a = *this;
    int128 t = b;
    
    this->lo = 0ull;
    this->hi = 0ll;
    
    for (unsigned int i = 0; i < 128; ++i) {
        if (t.lo & 1)
            *this += a << i;
        
        t >>= 1;
    };
    
    return *this;
};


int128 int128::div (const int128 & divisor, int128 & remainder) const throw () {
    if (!divisor)
        return 1u / (unsigned int) divisor.lo;
        // or RaiseException (EXCEPTION_INT_DIVIDE_BY_ZERO,
        //                    EXCEPTION_NONCONTINUABLE, 0, NULL);
    
    int128 ds = (divisor < 0) ? -divisor : divisor;
    int128 dd = (*this < 0) ? -*this : *this;

    // only remainder
    if (ds > dd) {
        remainder = *this;
        return (int128)0;
    };
    
    int128 r = (int128)0;
    int128 q = (int128)0;
//    while (dd >= ds) { dd -= ds; q += 1; }; // extreme slow version

    unsigned int b = 127;
    while (r < ds) {
        r <<= 1;
        if (dd.bit (b--))
            r.lo |= 1;
    };
    ++b;
    
    while (true)
        if (r < ds) {
            if (!(b--)) break;
            
            r <<= 1;
            if (dd.bit (b))
                r.lo |= 1;
            
        } else {
            r -= ds;
            q.bit (b, true);
        };

    // correct
    if ((divisor < 0) ^ (*this < 0)) q =- q;
    if (*this < 0) r =- r;
    
    remainder = r;
    return q;
};

bool int128::bit (unsigned int n) const throw () {
    n &= 0x7F;
    
    if (n < 64)
        return this->lo & (1ull << n);
    else
        return this->hi & (1ull << (n - 64));
};

void int128::bit (unsigned int n, bool val) throw () {
    n &= 0x7F;
    
    if (val) {
        if (n < 64) this->lo |= (1ull << n);
               else this->hi |= (1ull << (n - 64));
    } else {
        if (n < 64) this->lo &= ~(1ull << n);
               else this->hi &= ~(1ull << (n - 64));
    };
};


int128 & int128::operator >>= (unsigned int n) throw () {
    n &= 0x7F;

    if (n > 63) {
        n -= 64;
        this->lo = this->hi;
        
        if (this->hi < 0) this->hi = -1ll;
                     else this->hi = 0ll;
    };
    
    if (n) {
        // shift low qword
        this->lo >>= n;
        
        // get lower N bits of high qword
        uint64_t mask = 0ull;
        for (unsigned int i = 0; i < n; ++i) mask |= (1 << i);
        
        // and add them to low qword
        this->lo |= (this->hi & mask) << (64 - n);
    
        // and finally shift also high qword
        this->hi >>= n;
    };
    
    return *this;
};

int128 & int128::operator <<= (unsigned int n) throw () {
    n &= 0x7F;

    if (n > 63) {
        n -= 64;
        this->hi = this->lo;
        this->lo = 0ull;
    };

    if (n) {
        // shift high qword
        this->hi <<= n;
        
        // get higher N bits of low qword
        uint64_t mask = 0ull;
        for (unsigned int i = 0; i < n; ++i) mask |= (1 << (63 - i));
        
        // and add them to high qword
        this->hi |= (this->lo & mask) >> (64 - n);
    
        // and finally shift also low qword
        this->lo <<= n;
    };
    
    return *this;
};

bool int128::operator ! () const throw () {
    return !(this->hi || this->lo);
};

int128 & int128::operator |= (const int128 & b) throw () {
    this->hi |= b.hi;
    this->lo |= b.lo;
    
    return *this;
};

int128 & int128::operator &= (const int128 & b) throw () {
    this->hi &= b.hi;
    this->lo &= b.lo;
    
    return *this;
};

int128 & int128::operator ^= (const int128 & b) throw () {
    this->hi ^= b.hi;
    this->lo ^= b.lo;
    
    return *this;
};

bool operator <  (const int128 & a, const int128 & b) throw () {
    if (a.hi == b.hi) {
        if (a.hi < 0)
            return (int64_t) a.lo < (int64_t) b.lo;
        else
            return a.lo < b.lo;
    } else
        return a.hi < b.hi;
};

bool operator == (const int128 & a, const int128 & b) throw () {
    return a.hi == b.hi && a.lo == b.lo;
};
bool operator && (const int128 & a, const int128 & b) throw () {
    return (a.hi || a.lo) && (b.hi || b.lo);
};
bool operator || (const int128 & a, const int128 & b) throw () {
    return (a.hi || a.lo) || (b.hi || b.lo);
};

